284 lines
9.2 KiB
C
284 lines
9.2 KiB
C
/* Type-safe arrays which grow dynamically.
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Copyright 2021-2023 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Paul Eggert and Bruno Haible, 2021. */
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#ifndef _GL_DYNARRAY_H
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#define _GL_DYNARRAY_H
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/* Before including this file, you need to define:
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DYNARRAY_STRUCT
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The struct tag of dynamic array to be defined.
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DYNARRAY_ELEMENT
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The type name of the element type. Elements are copied
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as if by memcpy, and can change address as the dynamic
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array grows.
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DYNARRAY_PREFIX
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The prefix of the functions which are defined.
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The following parameters are optional:
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DYNARRAY_ELEMENT_FREE
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DYNARRAY_ELEMENT_FREE (E) is evaluated to deallocate the
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contents of elements. E is of type DYNARRAY_ELEMENT *.
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DYNARRAY_ELEMENT_INIT
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DYNARRAY_ELEMENT_INIT (E) is evaluated to initialize a new
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element. E is of type DYNARRAY_ELEMENT *.
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If DYNARRAY_ELEMENT_FREE but not DYNARRAY_ELEMENT_INIT is
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defined, new elements are automatically zero-initialized.
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Otherwise, new elements have undefined contents.
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DYNARRAY_INITIAL_SIZE
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The size of the statically allocated array (default:
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at least 2, more elements if they fit into 128 bytes).
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Must be a preprocessor constant. If DYNARRAY_INITIAL_SIZE is 0,
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there is no statically allocated array at, and all non-empty
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arrays are heap-allocated.
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DYNARRAY_FINAL_TYPE
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The name of the type which holds the final array. If not
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defined, is PREFIX##finalize not provided. DYNARRAY_FINAL_TYPE
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must be a struct type, with members of type DYNARRAY_ELEMENT and
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size_t at the start (in this order).
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These macros are undefined after this header file has been
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included.
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The following types are provided (their members are private to the
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dynarray implementation):
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struct DYNARRAY_STRUCT
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The following functions are provided:
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*/
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/* Initialize a dynamic array object. This must be called before any
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use of the object. */
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#if 0
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static void
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DYNARRAY_PREFIX##init (struct DYNARRAY_STRUCT *list);
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#endif
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/* Deallocate the dynamic array and its elements. */
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#if 0
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static void
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DYNARRAY_PREFIX##free (struct DYNARRAY_STRUCT *list);
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#endif
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/* Return true if the dynamic array is in an error state. */
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#if 0
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static bool
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DYNARRAY_PREFIX##has_failed (const struct DYNARRAY_STRUCT *list);
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#endif
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/* Mark the dynamic array as failed. All elements are deallocated as
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a side effect. */
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#if 0
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static void
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DYNARRAY_PREFIX##mark_failed (struct DYNARRAY_STRUCT *list);
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#endif
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/* Return the number of elements which have been added to the dynamic
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array. */
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#if 0
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static size_t
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DYNARRAY_PREFIX##size (const struct DYNARRAY_STRUCT *list);
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#endif
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/* Return a pointer to the first array element, if any. For a
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zero-length array, the pointer can be NULL even though the dynamic
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array has not entered the failure state. */
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#if 0
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static DYNARRAY_ELEMENT *
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DYNARRAY_PREFIX##begin (const struct DYNARRAY_STRUCT *list);
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#endif
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/* Return a pointer one element past the last array element. For a
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zero-length array, the pointer can be NULL even though the dynamic
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array has not entered the failure state. */
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#if 0
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static DYNARRAY_ELEMENT *
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DYNARRAY_PREFIX##end (const struct DYNARRAY_STRUCT *list);
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#endif
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/* Return a pointer to the array element at INDEX. Terminate the
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process if INDEX is out of bounds. */
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#if 0
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static DYNARRAY_ELEMENT *
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DYNARRAY_PREFIX##at (struct DYNARRAY_STRUCT *list, size_t index);
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#endif
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/* Add ITEM at the end of the array, enlarging it by one element.
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Mark *LIST as failed if the dynamic array allocation size cannot be
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increased. */
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#if 0
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static void
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DYNARRAY_PREFIX##add (struct DYNARRAY_STRUCT *list,
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DYNARRAY_ELEMENT item);
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#endif
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/* Allocate a place for a new element in *LIST and return a pointer to
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it. The pointer can be NULL if the dynamic array cannot be
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enlarged due to a memory allocation failure. */
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#if 0
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static DYNARRAY_ELEMENT *
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DYNARRAY_PREFIX##emplace (struct DYNARRAY_STRUCT *list);
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#endif
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/* Change the size of *LIST to SIZE. If SIZE is larger than the
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existing size, new elements are added (which can be initialized).
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Otherwise, the list is truncated, and elements are freed. Return
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false on memory allocation failure (and mark *LIST as failed). */
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#if 0
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static bool
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DYNARRAY_PREFIX##resize (struct DYNARRAY_STRUCT *list, size_t size);
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#endif
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/* Remove the last element of LIST if it is present. */
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#if 0
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static void
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DYNARRAY_PREFIX##remove_last (struct DYNARRAY_STRUCT *list);
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#endif
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/* Remove all elements from the list. The elements are freed, but the
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list itself is not. */
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#if 0
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static void
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DYNARRAY_PREFIX##clear (struct DYNARRAY_STRUCT *list);
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#endif
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#if defined DYNARRAY_FINAL_TYPE
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/* Transfer the dynamic array to a permanent location at *RESULT.
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Returns true on success on false on allocation failure. In either
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case, *LIST is re-initialized and can be reused. A NULL pointer is
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stored in *RESULT if LIST refers to an empty list. On success, the
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pointer in *RESULT is heap-allocated and must be deallocated using
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free. */
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#if 0
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static bool
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DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *list,
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DYNARRAY_FINAL_TYPE *result);
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#endif
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#else /* !defined DYNARRAY_FINAL_TYPE */
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/* Transfer the dynamic array to a heap-allocated array and return a
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pointer to it. The pointer is NULL if memory allocation fails, or
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if the array is empty, so this function should be used only for
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arrays which are known not be empty (usually because they always
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have a sentinel at the end). If LENGTHP is not NULL, the array
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length is written to *LENGTHP. *LIST is re-initialized and can be
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reused. */
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#if 0
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static DYNARRAY_ELEMENT *
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DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *list,
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size_t *lengthp);
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#endif
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#endif
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/* A minimal example which provides a growing list of integers can be
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defined like this:
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struct int_array
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{
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// Pointer to result array followed by its length,
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// as required by DYNARRAY_FINAL_TYPE.
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int *array;
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size_t length;
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};
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#define DYNARRAY_STRUCT dynarray_int
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#define DYNARRAY_ELEMENT int
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#define DYNARRAY_PREFIX dynarray_int_
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#define DYNARRAY_FINAL_TYPE struct int_array
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#include <malloc/dynarray-skeleton.c>
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To create a three-element array with elements 1, 2, 3, use this
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code:
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struct dynarray_int dyn;
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dynarray_int_init (&dyn);
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for (int i = 1; i <= 3; ++i)
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{
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int *place = dynarray_int_emplace (&dyn);
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assert (place != NULL);
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*place = i;
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}
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struct int_array result;
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bool ok = dynarray_int_finalize (&dyn, &result);
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assert (ok);
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assert (result.length == 3);
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assert (result.array[0] == 1);
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assert (result.array[1] == 2);
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assert (result.array[2] == 3);
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free (result.array);
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If the elements contain resources which must be freed, define
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DYNARRAY_ELEMENT_FREE appropriately, like this:
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struct str_array
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{
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char **array;
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size_t length;
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};
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#define DYNARRAY_STRUCT dynarray_str
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#define DYNARRAY_ELEMENT char *
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#define DYNARRAY_ELEMENT_FREE(ptr) free (*ptr)
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#define DYNARRAY_PREFIX dynarray_str_
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#define DYNARRAY_FINAL_TYPE struct str_array
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#include <malloc/dynarray-skeleton.c>
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*/
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/* The implementation is imported from glibc. */
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/* Avoid possible conflicts with symbols exported by the GNU libc. */
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#define __libc_dynarray_at_failure gl_dynarray_at_failure
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#define __libc_dynarray_emplace_enlarge gl_dynarray_emplace_enlarge
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#define __libc_dynarray_finalize gl_dynarray_finalize
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#define __libc_dynarray_resize_clear gl_dynarray_resize_clear
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#define __libc_dynarray_resize gl_dynarray_resize
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#if defined DYNARRAY_STRUCT || defined DYNARRAY_ELEMENT || defined DYNARRAY_PREFIX
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# ifndef _GL_LIKELY
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/* Rely on __builtin_expect, as provided by the module 'builtin-expect'. */
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# define _GL_LIKELY(cond) __builtin_expect ((cond), 1)
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# define _GL_UNLIKELY(cond) __builtin_expect ((cond), 0)
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# endif
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/* Define auxiliary structs and declare auxiliary functions, common to all
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instantiations of dynarray. */
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# include <malloc/dynarray.gl.h>
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/* Define the instantiation, specified through
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DYNARRAY_STRUCT
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DYNARRAY_ELEMENT
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DYNARRAY_PREFIX
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etc. */
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# include <malloc/dynarray-skeleton.gl.h>
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#else
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/* This file is being included from one of the malloc/dynarray_*.c files. */
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# include <malloc/dynarray.h>
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#endif
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#endif /* _GL_DYNARRAY_H */
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